Variable velocity pneumatic gun system



Nov. 22, 1960 s. a. MOORHEAD, JR 2,950,977

VARIABLE VELOCITY PNEUMATIC GUN SYSTEM Filed April 21, 1959 3 Sheets-Sheet 1 ATTORNEY Nov. 22, 1960 s. B. MOORHEAD, JR 2,960,977

VARIABLE VELOCITY PNEUMATIC GUN SYSTEM Filed April 21, 1959 S Sheets-Sheet 2 R0". Y J M m M n 1% A w M a y m 1 L! m w 5 w w a 41/ mm Q v NW Wm Wm R .f

Nov. 22; 1960 s. B. MOORHEAD, JR 2,960,977

VARIABLE VELOCITY PNEUMATIC GUN SYSTEM Filed April 21, 1959 3 Sheets-Sheet 3 INVENTOR SETH B. MOORHEAQJR.

ATTORNEY United States Patent VARIABLE VELOCITY PNEUMATIC GUN SYSTEM Seth B. Moorhead, Jr., Orlando, Fla., assignor, by mesne assignments, to the UnitedStates of America as represented by the Secretary of the Navy Filed Apr. 21, 1959, Ser. No. 807,961

7 Claims. ((11. 124-11) The present invention relates to a variable velocity pneumatic gun system and more particularly to a pneumatic gun system for ejecting a missile at any selected muzzle velocity within a specified range.

Pneumatic gun systems previously used to perform the operation achieved by the instant invention were overcomplicated in design and in the number of parts used, and operation sequence required numerous steps in firing the gun, and it was also necessary to seal the breech before firing the gun. Moreover, the firing valve used in prior devices of this type was not dependable or eflicient and the weight of the gun was undesirably great for transportation in aircraft.

By the use of the present invention, applicant has devised a means to eject a marine marker, or any other round of similar shape and weight, at any selected muzzle velocity between 30 and 200 knots with a minimum of weight and space. and sequences have been considerably reduced while the range of muzzle velocity has increased from the previous limitsof 90 to 200 knots.

An object of the present invention is the provision of a pneumatic gun which may be fired at any selected velocity within a specified range.

Another object is to provide a pneumatic gun system having a minimum of moving parts and readily convenient maintenance.

A further object of the invention is the provision of a gun system of comparatively small weight for transportation in aircraft.

A final object of the invention is to provide a gun system having safety features to prevent mi'sfiring of a projectile within the barrel of the gun.

Other objects and many of the attendant advantages of this invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

Fig. 1 is a diagrammatic perspective view of the gun system with the breech closed.

Fig. 2 illustrates a schematic secticnal view of the gun system including the electrical wiring arrangement.

Fig. 3 is a sectional view of the breech mechanism taken along line 3-3 of Fig. 1.

Fig. 4 illustrates a sectional view of the detent mechanism.

Fig. 5 is a view, partly in section, of the striker taken along line 5--5 of Fig. 2 and looking in the direction of the arrows.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, there is shown in Fig. l a pneumatic gun assembly which utilizes a charge of compressed air from a compressor (not shown) and a reservoir-11. A pressure regulator valve 12 having an indi- Further, the number of moving parts A 2,960,977 Patented Nov. 22, 1960 cator 13 and a safety control indicator 14 are connected t the reservoir and lead to a valve 15 for charging an accumulator 16. Between the valve 15 and the accumulater, a check valve 17 is installed to insure a unidirectional flow of air. The rearward portion of the gun barrel 18 is enclosed by the accumulator 16 and is joined thereto by a breech assembly 19 including a striker mechanism 20. As shown in Fig. 2, the projectile 21 is initially positioned in the rearward portion of the barrel 18 adjacent the accumulator and is fired by the interaction of a release valve 22 and the striker mechanism 20. After the projectile starts down the barrel 18, its sides close a detent switch to activate it by a means to be described hereinafter.

It is to be noted that the missile 21 is required to be ejected from the gun and the aircraft at an aft velocity equal and opposite to the aircrafts estimated ground speed; the exit velocity of the store being determined by the compressed air entering the accumulator 16. Since the exit muzzle velocity is always equal and opposite to the aircraft velocity, the trajectory is substantially straight down. The trajectory, therefore, is not affected by altitude and only one adjustment (aircraft speed) is necessary.

The firing valve, comprised of a series of O-seals, is shown more clearly in Fig. 3. It is arranged to close and seal completely and also to open instantaneously with the use of only one moving part. The firing valve assembly is assembled within an outer collar 51 which is screw threaded on accumulator 16, and is comprised of a seal plate 52 in which O-ring seals 24 and 2411 are mounted in sealing engagement with both accumulator l6 and barrel 18. Another seal plate 53 contacts seal plate 52 and contains O-ring 25 which seals against rearward leakage from accumulator l6. O-ring 27 is mounted between seal plate 53 and a flanged end plate 54 which is connected by peripheral screws (not shown) to collar 51. O-ring 27 is the single valve means which a'lows accumulated air pressure to pass into barrel 18 on firing of the gun. Passageway 56 passes through plate 52 and connects accumulator 16 with passageway 57 which is formed between plates 52 and S4 and communicates with barrel 18. Breech 58 is rotatably mounted in the flanged end plate 54. O-ring 26 is mounted between breech 58 and flanged end plate 54 to prevent leakage. When charging valve 15 (Fig. 2) is opened, high pressure air enters accumulator 16 via duct 28 and simultaneously passes through a groove 29 behind O-ring 27 thereby forcing the O-ring to seat and seal off the barrel. As release valve 22 is opened, the high pressure air in groove 29 is released through duct 30 into the atmosphere. The air in the accumulator 16 then forces the O ring back to the position shown in phantom lines in Figs. 2 and 3, thus permitting air to enter the barrel 18 and force the projectile 21 forward. A firing valve utilizing only one moving part is thus achieved whereby maintenance is minimized and reliability is of a high order.

After'a slight movement forward, the projectile 21 actuates the detent switch 23 shown more clearly in Fig. 4. The detent is comprised of a micros-witch 31, leaf spring 32 and hermetic terminals 33, all of which are housed in a casing 34. As the projectile 21 proceeds through the barrel 18, the leaf spring 32 is forcedupwardly by theprojectiles conical surface. The spring is designed to hold the projectile at the base of the barrel with a force large enough to prevent it from traveling down the barrel by virtue of its own inertia during loading. However,thespring is weak enough to. release the store when the air pressure is applied. As the store moves down the barrel, it pushes thespring in the manner shown in phantom lines in Fig. 4 and closes the microswitch 31. This closes the circuit to the striker mechanism 20 and causes the store to be ignited.

The striker mechanism is required to ignite the marker only when an ejection pressure below a minimum pressure is used. When pressure above said limit is used, the projectile is designed to be ignited by the pressure itself. In order to detonate the store with the striker, a pair of handles 35 are pivotally attached to the breech 58 as shown in Fig. 5. On each handle and adjacent one end thereof is a pivoted tong 36 adapted to be inserted within a recess 37 of a cylinder 38. A spring 39 encloses the cylinder 38 and a small shaft 40 with the spring being normally in compressed condition. A pin 41 on the shaft is adapted to fit within a bayonet slot 42 on cylinder 38 to insure that the firing pin 43 will not move forward accidentally. By means of recesses on each side of a casing 44, the tongs 36 are permitted to contact the recessed cylinder. The striker pin 43 is spring loaded and actuated by a solenoid 45. It is necessary to cock the striker each time the breech is opened and is performed by pulling the handles 35 toward each other. The handles also operate to open the breech 58. The solenoid circuit, best shown in Fig. 2, is comprised of the solenoid 45, the detent switch 23, a second solenoid 46 and a firing switch 47 in series for precautionary measures. In this manner, the striker pin 43 will not ignite the projectile unless it has moved past the detent 23 and the firing switch 45 is closed.

The operation of the gun system is as follows. The pressure regulator valve 12 is adjusted and set to the desired muzzle velocity for firing the projectile 21 in an opposite direction to that of the aircraft motion. This velocity corresponds to the aircrafts estimated ground speed when the projectile 21 is a marker so that the marker drops vertically and negates the inertia imparted to it by the moving aircraft. The charging valve 15 is then opened and closed to fill the accumulator 16 with air compressed to the required number of pounds per square inch. The breech 58 is opened, the projectile 21 is inserted and the breech is then closed. The projectile is thus ready for firing. The store may be rejected, if required, by merely re-opening the breech and withdrawing the store from the barrel. The accumulator pressure is prevented from entering the barrel by the series of O-rings 24, 25, 26, 27 held closed by a balanced pressure.

When the firing switch 47 is closed, the firing solenoid 46 opens the release valve 22, thereby releasing the air pressure on the aft side of the O-ring assembly into the atmosphere. This allows the compressed air in the acculator to enter the barrel 18 and forces the striker pin 43 forward which, being lighter than the projectile 21, overtakes the aft end of the projectile and strikes a firing piston (not shown) in it, driving the piston home as the projectile travels through the barrel. It can be seen from Fig. 2 that the striker mechanism 20 cannot operate unless both the firing switch 47 is closed and the projectile has moved far enough through the barrel to close the detent switch 23. If the striker circuit is shorted, the projectile is ignited simultaneously with firing; if the circuit should fail and the pressure is below the minimum requirement, the unignited projectile is merely ejected. The gun system described above is thus capable of ejecting a projectile, such as a marker, at any selected muzzle velocity between 30 and 200 knots and accomplishes this object with a minimum of space and weight.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood, that within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.

What is claimed is: 1

1. A pneumatic gun comprising in combination, a

barrel, an accumulator encompassing a portion of said barrel, a breechblock assembly mounted on said accumulator, a passageway formed in said breechblock assembly connecting said accumulator with said barrel, a pressure groove formed in said breechblock assembly, a high pressure inlet connected to both said accumulator and said pressure groove, a relief valve connected to said pressure groove, a firing valve means mounted in said breechblock assembly between said pressure groove and said accumulator and adapted to block said passageway connecting said accumulator with said barrel, an electric circuit means having a switch, said electric circuit means being connected to said relief valve so that on closing said switch said relief valve opens to atmosphere whereby a pressure differential arises across said firing valve means causing it to no longer block said passageway so that high pressure may pass into said barrel.

2. The combination as claimed in claim 1 wherein said firing valve means comprises an annular plate, a flanged plate and an O-ring mounted between said annular plate and said flanged plate.

3. The combination of claim 2 further comprising a reservoir, a pressure regulating valve, a charging valve and a check valve, said reservoir and said valves being joined by ducts to said accumulator, whereby air from said reservoir passes through said valves and is stored in said accumulator.

4. A pneumatic gun comprising in combination, a barrel, an accumulator encompassing a portion of said barrel, a breechblock assembly mounted on said accumulator, a passageway formed in said breechblock assembly connecting said accumulator with said barrel, a pressure groove formed in said breechblock assembly, a high pressure inlet connected to both said accumulator and said pressure groove, a firing valve means mounted in said breechblock assembly between said pressure groove and said accumulator and adapted to block said passageway connecting said accumulator with said barrel, a striker means connected to said breechblock assembly, an electric circuit means having a firing switch and a detent switch, said electric circuit means being connected to said relief valve and said striker means so that on closing said firing switch said relief valve opens to atmosphere causing a pressure differential across said firing valve means which causes said passageway between said accumulator and barrel to open and also closes said detent switch which releases said striker means.

5. The combination as claimed in claim 4 wherein said firing valve means comprises an annular plate, a flanged plate and an O-ring mounted between said annular plate and said flanged plate.

6. The combination as claimed in claim 5, wherein said striker means comprises a pair of handles pivotally attached to said breechblock, a tong connected to each of said handles, a cylinder into which said tongs extend, a spring enclosing one end of said cylinder, a striker pin connected to said cylinder, and means for imposing the load of said spring on said cylinder so that said striker pin will strike any store within said barrel.

7. A pneumatic gun comprising in combination, a barrel having a fore and aft portion, an accumulator mounted on the aft portion of said barrel, a collar screwed on the aft end of said accumulator, a seal plate having a passageway therethrough mounted in sealing relationship with said accumulator and the aft portion of said barrel, an annular plate mounted axially rearward of said seal plate in sealing relationship therewith, a flanged plate having a groove therein mounted axially rearward of said annular plate, a breech mounted in said flanged plate having a hole therein, a seal mounted between said breech and said flanged plate, a passageway formed by said sealplate and said flanged plate in communication with said barrel, an O-ring mounted between said annular plate and said flanged plate so as to block said passageway, a high pressure inlet connected to both said accumulator and said groove, an outlet from said groove, a relief valve connected to said outlet, a reservoir, a pressure regulating valve, a charging valve and a check valve, said reservoir and said valves connected by ducts to said high pressure inlet, a leaf spring mounted on the inside of the fore portion of said barrel, a micro-switch mounted radially outward of said leaf spring so that when said leaf spring is depressed said micro-switch is closed, a pair of handles pivotally attached to said breech, a tong connected to each of said handles, a cylinder into which said tongs extend, a spring connected to one end of said cylinder, a striker pin connected to said cylinder and mounted in said hole through said breech, release means for imposing the load of said spring on said cylinder so that said striker pin will strike any store within said barrel, an electric circuit 15 means having a firing switch connected to said relief valve, said micro-switch and said release means whereby when the firing switch is closed the relief valve is opened thereby releasing the air pressure in said groove and said O-ring moves so as to open said passageway, whereupon air flows from said accumulator through said passageway into said barrel and forces a store into said fore portion of said barrel, Where it contacts and depresses said leaf spring and closes said micro-switch which closes the circuit means connected to said release means and triggers said striker pin which ignites the store before it is ejected 10 from the barrel by air pressure.

References Cited in the file of this patent UNITED STATES PATENTS 1,298,447 Bradford Mar. 25, 1919 1,301,327 Slate Apr. 22, 1919 2,780,213 Colling et a1 Feb. 5, 1957 

